Current Standard Solution:
Carrier offers the ability to control an exhaust fan with a HyperStat using the Conventional Package Unit (CPU) profile.
Opportunity :
There are scenarios where there is an opportunity for increased energy savings by scheduling and controlling exhaust fans in a building.
Solution:
Using a HyperStat to control an exhaust fan is relatively straightforward. The components needed are a 24VAC power source, a pilot relay such as a RIB with heavy-duty contacts rated for a minimum of 10A, and a current transformer (CT) used to monitor the amperage and status of the exhaust fan. Please refer to the application drawing and callout detail below.
How does it work? :
- The hyperstat switches 24VAC through relay 3 (G) terminal to the 24VAC contacts on the pilot(RIB) relay.
- The pilot (RIB) relay then closes its secondary heavy-duty contacts where the power to the exhaust fan motor is run to common and the normally open contact then to the exhaust fan motor.
- The current transformer (CT) is installed around the lead going to the motor. This is used to measure fan motor amperage and status.
Mapping and Configuration :
- The exhaust fan can be controlled by configuring the hyperstat using the following options.
-
Fan Low Speed
A relay mapped to Fan Low Speed gives you the following selectable fan mode options on the hyperstat.
- Fan Low Current Occupied Period - The fan runs during the current occupancy period. Ex. Forced Occupied, Occupancy Enable
- Fan Low Occupied Period- Fan operates during the current scheduled period. Ex Building/Zone/Named/Special Event schedule.
- Fan Low All Times- The fan operates during scheduled occupied/unoccupied times. 24/7 operation.
Occupied Enable A relay mapped to Occupied Enable is "ON" whenever the zone is in an occupied schedule and "OFF" when in an unoccupied schedule. No selectable fan mode options are available on the HyperStat. The only option available is "OFF".
In addition, we want to enable Analog Input 1 and set the amperage measurement range for the current transformer (CT) selectable 0-10A, 0-20A, and 0-50A. This selection should be based on the motor's amperage found on the manufactures data plate/sticker on the motor housing.
Result:
- For a relatively low price point, exhaust fans can be controlled and monitored using a Carrier Smart Circuit Package w/HyperStat.
- Exhaust Fans will now have customized operation by utilizing a Building/Zone/Named/Special Event Schedule
For Additional Information, See the Following:
HyperStat Overview and Installation
HyperStat Conventional Packaged Unit Profile
https://climavision.zendesk.com/hc/en-us/articles/18934300150675-HyperStat-CPU
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